1. Field of the Invention
The present invention pertains to a method for completing and producing wells in unconsolidated formations by developing an in situ sand pack of the relatively coarse formation sand particles in a dilatant zone of mechanically stable formation material extending outward from the wellbore.
2. Background
The completion and production of hydrocarbon fluids such as crude oil from relatively unconsolidated sands is complicated by the tendency to produce two much sand with the produced fluid resulting in the breakdown of equipment, plugging of at least portions of the wellbore and the production tubing string and/or complete collapse of the formation material into the wellbore. Various techniques have been contemplated for stabilizing a formation prior to production of fluids including the injection or substances which stabilize or consolidate the formation material in the vicinity of the wellbore. For various reasons, including the composition of the formation, prior art processes often are not satisfactory and they complicate the wellbore completion process.
However, it has been observed in laboratory studies that, when fluids are produced at relatively high rates into a cavity formed in an unconsolidated formation, a dilatant zone is created around the cavity into which the produced fluid flows without producing a significant amount of sand or fine formation material. Based on this observation and other factors, the present invention has been developed to provide an improved method of completing and producing high productivity wells in substantially unconsolidated sands.